Convergence improvement of iterative learning control

This paper deals with the problem of iterative learning control for a class of uncertain nonlinear systems with unknown time-varying control coefficients. The uncertainties of the system are time-varying and may depend on states of the system. In the previous studies, it is only guaranteed that the tracking error converges to zero for each point in the iteration interval if the saturation control is not employed. In the paper, a iterative learning control law is presented without use of the saturation control, which guarantees that the tracking error converges to zero uniformly.